home.md

-Findings with the Elastic Search REST API
-===========================================
+#Findings with the Elastic Search REST API
+
+
+## Different search query methods
 
-Different search query methods
---------------------------------
 **(Multi-)match** vs. **(simple_)query_string**
 - **Match**: Returns documents that match a provided text, number, date or boolean value
 - **query_string**: Returns documents based on a provided query string, using a parser with a strict syntax. (=> simple_query_string more dynamic than match and easier and more robiust syntax than query_string)
 
-Improving the search
---------------------
-Using simple_query_string in the following examples. For quite a few functionalities one can use multi-match too. But simple_query_string is more flexible!
+## Improving the search
+
+Using simple_query_string in the following examples.
+
+### Basic title search
 
 Let's start with a simple example (GET: https://localhost:9200/_search):
 ```json
@@ -34,6 +36,8 @@ The returned results contain 5 documents:
 
 The problem is that this input either searches for the string *python* OR the string *programming* in the title.
 
+### AND & OR operators
+
 To search for results containing both words the *default_operator* parameter (default: "or") needs to be set to "and":
 ```json 
 {
@@ -47,9 +51,40 @@ To search for results containing both words the *default_operator* parameter (de
 }
 ```
 
-Now no result is returned, since no title of the documents contains both words. We can search more fields by adding the path to the *fields* parameter:
+Now no result is returned, since no title of the documents contains both words. 
+
+AND and OR can also be specified in the query string with & and |. Other operations can be used with the [simple query string syntax](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-simple-query-string-query.html#simple-query-string-syntax).
+
+### Search multiple fields
+
+We can search more fields by adding the path to the *fields* parameter:
 ```json
 "fields": ["_content.Page.Content.Title.~",
                 "_content.Page.Content.Body.~"]
 ```
 Now the returned search results contain 11 Documents.
+
+### Use Fuzziness for typos
+
+Since the searches only look for exact matches of strings and keywords the following search does not return any results:
+```json
+{
+"query": {
+    "simple_query_string" : {
+        "query": "Pytho",
+        "fields": [
+                "_content.Page.Content.Title.~",
+                "_content.Page.Content.Body.~"
+            ],
+        "default_operator": "and"
+    }
+  }
+}
+```
+To solve this issue we add automatic fuzziness to the query.
+```json
+"query": "Pytho~"
+```
+Now we retrieve 28 different documents.
+The Edit-Distances for fuzziness can be specified behind the like `"query": "Pytho~2"` but the automatic fuzziness setting is [recommended](https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#fuzziness) as it takes term length into account.
+